Running tools have been utilized in the oil industry for many years for the purpose of positioning well apparatus such as mechanical, hydraulic, electric and/or explosive devices in well bores. Many such apparatus are locked into a position in a well bore by means of a particular configuration of grooves or "profile" formed in the tubing or well bore wall into which a latch device on the apparatus lands.
Such tools have, in the past, been successful in the positioning of the well bore apparatus in the desired position due to the use of the profile. However, problems have occurred when tight spots in the tubing or well bore were encountered during lowering of the apparatus. Also, problems have occurred as a result of the running tool being dropped in the well bore and falling into the released well apparatus. The problem may be particularly acute when the well apparatus is a firing mechanism for a perforating gun or the like.
An example of the difficulties encountered in lowering the well apparatus into the well bore occurs when the apparatus becomes stuck in the well bore. When the apparatus sticks, it is usually necessary to work the apparatus in an effort to get the apparatus through the tight spot. Such working usually consists of applying a tensile force to the running tool and well apparatus which is attached thereto. Occasionally, such tensile force exceeds the force necessary to actuate the running tool and, consequently, the well apparatus is released prematurely.
Most of the running tools constructed heretofore have utilized some form of shear device holding the parts of the running tool in the running position. The shear devices are usually parted by applying a tensile force to the running tool that will exert a force thereon sufficient to cause failure of the shear device.
Also, such running tools have not, insofar as is known, incorporated means for preventing the running tool from being inadvertently dropped into the well bore in the event that the running tool becomes disengaged from the wire line or tubing used to move the running tool through the well bore. As mentioned before, this may cause premature firing of a perforating gun or other charge, and could result in malfunctioning of whatever type of well apparatus was previously positioned in the well bore.
An object of this invention is to provide a running tool for positioning well apparatus in a well bore that can be manipulated with safety in the event that the well apparatus becomes stuck, that utilizes no shear devices, and that can be moved only upwardly in the well bore after the well apparatus has been released therefrom.